CI dry run: gtk4 branch

.changes/gtk4.md

@@ -0,0 +1,5 @@
+---
+"muda": minor
+---
+
+Port the Linux backend from GTK3 to GTK4 (`gtk4` 0.11, `glib` 0.22). Every public method keeps its name and signature shape; the gtk types in returns and bounds follow the toolkit (`PopoverMenu`/`PopoverMenuBar`, `Widget` bounds), and `ContextMenu::gtk_context_menu` is retained on GTK4. Raises MSRV to 1.92.

.github/workflows/clippy-fmt.yml

@@ -29,7 +29,7 @@ jobs:
         if: matrix.platform == 'ubuntu-latest'
         run: |
           sudo apt-get update
-          sudo apt-get install -y libgtk-3-dev libxdo-dev libwebkit2gtk-4.1-dev
+          sudo apt-get install -y libgtk-3-dev libgtk-4-dev libxdo-dev libwebkit2gtk-4.1-dev
 
       - uses: dtolnay/rust-toolchain@stable
         with:

.github/workflows/test.yml

@@ -33,9 +33,11 @@ jobs:
         if: matrix.platform == 'ubuntu-latest'
         run: |
           sudo apt-get update
-          sudo apt-get install -y libgtk-3-dev libxdo-dev libwebkit2gtk-4.1-dev
+          sudo apt-get install -y libgtk-3-dev libgtk-4-dev libxdo-dev libwebkit2gtk-4.1-dev
 
-      - uses: dtolnay/rust-toolchain@1.73
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: "1.92"
       - run: cargo build
 
       - uses: dtolnay/rust-toolchain@stable